System of constant-speed motor control.



. L. BRADLEY.

SYSTEM OF CONSTANT SPEED MOTOR CONTROL.

APPLTCATION man OCT. 21. 1913.

1,201.;016. Patented Oct. 10,1916.

UNITED STATES PATENT OFFICE.

LYNDE BRADLEY, 0F MILWAUKEE, WISCONSIN.

SYSTEM OF CONSTANT-SPEED MOTOR'CONTROL.

Specification of Letters Patent.

Patented Oct. 10, 1916.

Application filed October 27, 1913. I Serial No. 797,415.

T 0 all whom it may concern Be it known that I, LYNDE BRADLEY,'a citizen of the United States, residing at Milwaukee, county of Milwaukee, and State of Wisconsin, have invented new and useful Improvements in Systems of Constant- Speed Motor Control, of which the following is a specification.

My invention relates to improvements in motor controlling apparatus of that class in which constant motor speed is an important consideration or in which a reliable method.

of speed control is required.

The object of my invention is to provide a system of controlling apparatus,'w'hich will be normally automatic in its operation,

*but which will be also subject to manual control where radical changes in conditions render a change in speed desirable. 'Also to provide means whereby the methods of control are .so interdependent that a manual controlling operation may change thebasis' upon which the automatic controlling de vices operate, whereupon said automatic devices will no, longer tend to maintain the.

to maintain a constant speed under uniform conditions, but with varying conditions of load,a constant speed ,will not be possible.

In the drawings Figure 1 is a diagrammatic view of a motor controlling apparatus as applied to a motor having a shunt, field.

Fig. 2 is'a' similar View showing my invention as it is applied to a seriesrmotor. Fig...

ing ofwthe magnetic s'wltch 25 t0 the minus line; 26, thus energizingv .the -magnetic line 3 is a view similar to'Fig. but 'with'a modified "form of operators switch.= Like parts are identified by the same ref erence characters throughout the several views. I 4

In Fig. 1 I have illustrated a motor armature 1 in operative relation to a compressible resistance unit 2 of the type shown'and described in Letters Patent, Number 1054902,

dated March 4th, 1913, issued to Lynde Bradley and Harry Bradley for mprovements in resistance devices. A series relay 3 and solenoid 4 cooperate to gradually compress the resistance unit in a series of operatlons terminating in a short circuiting switching operation which cuts out the unit 2 substantially as shown and described in former application filed by said Lynde Bradley and Harry Bradley for improvements m'short circuiting and'retrie apparatus, Serial Number 779694, filed July 18th, l913. The winding of solenoid 4 is connected across the line through the con tacts 5 and 6 of the relay 3 and another relay 7, the function of which is hereinafter described. The movable core 8 of solenoid 4 transmits motion, when thesolenoid is energized, through rod 9 andelbow crank 10 to compress the resistance column,'and relay 3 intermittingly interrupts the solenoid circuit whenever the current flow reaches the volume required for relay ope'ation, thus delaying the compressing operation by intermittingly de'e'nergizing the solenoid as de-- scribed in said former application. A spring 11 tends to retractlthe elbow crank lever 10 to non-compressing' po sition. When the compressing operation :is completed,

solenoid core contact 13 connects up a shunt through contact 1.4, which cuts out the resistance column and allows the motor to operate independently thereof.

Relay 7 is connected across the armature through operators switch 15, which is illusvtrated with its contacts developed, and which is adapted to insert into, or remove from the circuit of relay coil 7, one or more of the resistanceunits 16, 17 and 18. When the switch 15 is iii the position shown in Fig. 1, no current Will'be supplied tothe motor, 'but when it is moved to bring the contac'tfpoihts intersected by line B into engagement with the stationary contacts on line A, a circuit w'l be established from plus line 20 through ontact 21, switch contacts 22 and 23, contact 24, and the windswitch to swing its armature 27 :j-to circuit closing position and connecting up the circuit from plus line 20 through the armature 1 of the motor, resistance member 2, the winding of series relay 3, and through the armature switch lever 27 to'the minus line 26. The shunt field 30 of the motor will also be energized simultaneously, this being connected across the armature 1, resistance member 2 and'relay 3. A portion of the Q termined :deg

current'w/ill of course travel from switch contact 33 through stationary contact 34 and the winding of relay 7. A current path is also formed from plus line 20 across the 5 contacts 6 and 5 of relay 7, through the winding of solenoid 4 and across the contacts of series relay 3 to switch lever '27 to the minus line; 'The current-gtraversing the path last indicated, energizes 'solenoid 4 and 1t) compresses the resistance member as above explained, the compressing operation being delayed by series relay 3, which operates at a pie-determined current volume in the motor circuit and temporarilybreaks the circuit through solenoid until the acceleration of the n otor. builds up sutlicient counter-electro motive force in opposition to the voltage'of the supply .mains to reduce the current flow and allow relay 3 to again close, .20 the increased motor resistance being added to any increase in the resistance of member 2 due to any temporary reduction of pres- ;sure thereon. i ,1. V

1 When the motor reaches the desired speed 5 f orthe assumed :nljustment] ofswitch 15, 'relay 7 -will. operate to t ectricallyitfiti 'flm i h is nt i lrop across a 1 pre-ded finer i ts operation ial across the nsta nt'," thus the intensity ii oftheffield being uniform orsubstantially so.

:Assilming .no'w thatfswitch iflfi be re-adjusted to "bring contacts on .line C into on- ""co ntact"33 willtlieii-;lie '1no\'e(laway from P co1iti1ct 34, an'd jthe Icircui F through the winding of relay 7will thcrvbe establishet'l hthrough contacts 36 and 37 and resistance unit '16. \Vith this "adjustment, the resist- "'ance of unit 16 is added to the resistance of 1irelay7 and it "will 'th'erefore require a higher.

motor speed and: consequent moon-951a- :ance to cause sutlicient current to travel through the? relay to operate the latter. A further adjtistment of switch '15 to bring its contacts oniline D into re fstry with the fixed contact saon line A wi l i separate contacts 36 andj37, and the current will then travel through contacts 38 and 39, resistance units 17 and 16 to the winding of relay -;9' I,"thus making a greater motor Speed possiieing'wound Y gagementiwith the fixed contacts on line A."

ble. A further adjnstnn-nt f \'ltt'll 1-1 t bring contacts on line F, in registry with fixed contacts on line will t. til ll 'll the circuit of the relay through switch contact 40, fixed contact 41 and resistan eunits l l7 and 16. thus making ])U. llll( a still higher degree of motor speed. If maximum motor speed is desired. switch [.7 is"ad-- justed one step farther to wholly cut out relay 7 by bringing s wih h contacts on line F into registry witli Eyed contacts on line A, whereupon the circuit through solenoid l will be nnatlected y relay 7. and said solenoid will thereupon continue to increase the pressure uponresistance member .2, subject to the delays interposed by relay 3 until contact lil engages contact H and cuts out resistance member if aml relay 3. after which the motor will run at maximum speed.

'hen the relay 7 is in operation. any tendency which might result from the action .of relay 7 in causing abrupt changes of resistance will be offset by series relay which is always in control of the tll tlll.

through solenoid l and atfordst'fc same pro- ;tection tothe circuit as regards current oluiiie as relayI/Avcre'n t in use.

'lteferring" ttFFig. 2 it will be o served hat the construction and arrangement ol Q sthe parts is the same as in Fig. l. with (inonnect'edin circuit with the motor between on Sjlllctimi 'it is not possible to maintain "constant speedflmder varying loads. but "very reliable and convenient method of 1 ecd control is'atforded, which is peculiarly 'j adapted for the purpt'ises of remote control. 'as is nsually reqnircd'with cranes and hoists. Refcrring now-to Fig. it will be onserved that the construction and arrange- "ment is the same as in Fig. l. with the (X- nption that a swinging switch lever? is ""t-iiipio \'il in connection with fixed contacts '46 and 47. which lever and contacts corre re stance coilslt), l7 and IS. indicated in Fig. 1.; l have illustrated in Fig. 1 (mm pressible resistance column 50. -to which pressur is applied from lever 4.5 through ft-he cant 5i and compressing lever 52. liy employing acomprcssiblc resistance unit. 3". i the control-of relay becomes lli iite. xwvhcrebj an \',possib le motor speed may be .establish al, as distinguished from the step by;step speed changessecured in the construction shown in Fig. 7

I claim 1. An electrical control system including a motor armature in combination with a re lay having a coil bridged across such armature, means for anttmiatically varying the. resistance in the armature circuit to control exct btloi thatthc 'motor indicated is a riesmotor and'thc winding of relay 7 is he'jarn'iature land the lield 30;. ,With this spond respectively with contacts 22. fig 2f and 2+ in Fig. 1; Also In place of the step the current flow therein, means for manually varying the resistance in the relay coil circuit, and a device controlled by the relay for operating the resistance varyingmeans of the armature circuit.

2. An electrical control system for motors, including the combination with a motor armature, of a resistance medium controlling the flow of current to the armature, a solenoid adapted to automatically vary the resistance of said medium, a relay having a coil in circuit with the resistance medium and armature, and controlling the circuit through said solenoid, and another relay, coil connected across the armature and adapted when energized to break the circuit through said solenoid.

3. An electrical control system for motors, including the combination with a motor armature, of a resistance medium controlling the flow of current to the armature, a solenoid adapted to automatically vary the resistance of said medium, a relay having a coil in circuit with the resistance medium and armature, and controlling the circuitthrough said solenoid, and another relay coil connected across the armature and also con trolling the circuit through said solenoid, together with means for manually adding and subtracting resistance from the circuit of the last mentioned relay.

4. In an electrical control system, the combination of a field and an armature, a resistance medium, means for varying the resistance of said resistance medium, means for utilizing the current volume through the armature to control the resistance varying means and means bridged across the armature and adapted to automatically render said resistance varying means inoperative during a period when the potential across the armature exceeds a predetermined amount.

5. In an electrical control system, the combination of a motor containing a field and an armature, a resistance medium whose electrical conductivity is varied by pressure, an electro-magnetic means for exerting a variable pressure on said resistance medium, a: relay whose operating coil is connected in shunt with said armature, said relay being adapted to render the electro-magnetic pressure means inoperative when the potential across said armature reaches a predetermined degree. I

6. In an electrical control system, the combination of an electric motor containing a field and an armature, a resistance medium whose electrical conductivity is varied by pressure, means for exerting a variable pres sure on said resistance medium, and means for utilizing the rise and fall of the potential across the motor armature to govern the pressure exerting means.

7. In an electrical control system, the combination of a motor containing a. field and an armature, a resistance medium whose electrical conductivity is varied by pressure, an electro-magnetic means for exerting pressure on said resistance medium, a relay whose operating coil is connected in shunt with said armature, said relay being adapted to f govern the action of the pressure means.

8. In an electric current controller, the combination of an electric circuit, of a resistance medium whose electrical conduc tivity is varied by pressure, means for exert-ing pressure on said resistance medium, a

vice being adapted to control variations inthe resistance of said medium.

.10. In an electrical control system, the

combination of a motor armature, a variable resistance medlum in circuit with said armature,'a manually controlled swltch, a relay having a coil connected with the armature circuit between said variable resistance medium and the armature, and bridged across the armature to said switch, said relay being adapted to limit variations in the resistance of said resistance medium.

11. In an electrical control system, the combination of a motor armature, a variable resistance medium in circuit with said armature, a manually controlled switch, a relay having a. coil connected with the armature circuit between said variable resistance medium and thearmature, and bridged across the armature to said switch, said relay being adapted to limit variations in theresistance of said resistance medium, and said manually controlled switch being adapted to vary the resistance of the relay operating circuit.

In testimony whereof I afiix my signature in the presence of two witnesses.

LYNDE BRADLEY.

. Witnesses:

' L. C. WHEELER,

IRMA D. BREMER. 

